Microsoft is looking to rebrand the Lumia line following their purchase and integration with Nokia. That means a manufactured product series of new Microsoft Lumia products that seek to move away from the formula of the old company, and make it a part of the new one.
One of the first things Microsoft wanted to make clear with their announcement today was that Nokia Lumia phones are still being sold and supported, and so are not obsolete with the buyout. But that probably won’t be the case pretty soon, as they begin to phase out the old and bring in the new. At least, that is what can be gleaned from reading between the lines.